Ultrasoft X-ray emission spectroscopy (USXES) was used to investigate the electronic structures of FePt alloy included carbon nanocapsules (FePt@CNCs) and graphite nanosheets (GNSs). These materials were synthesized by electric plasma discharge in an ultrasonic cavitation field of liquid ethanol. Scanning and transmission electron microscopies were used to study the spatial structures and morphologies. The electronic structure of GNSs was compared with that of reference synthetic graphite powder and high surface area reduced graphene oxide (RGO) sheets with an average thickness of one graphene layer. Investigations of the electronic structures of the FePt@CNC and GNS mixture and GNSs obtained after magnetic separation of the mixture revealed that GNS graphene layers exhibited a smaller curvature than those of carbon nanocapsules, which widened the -subband of GNSs due to overlapping of the orbitals. Thicker GNSs had a narrower CKα emission band than RGO sheets, which was related to the greater overlapping of and orbitals in the more crumpled and corrugated RGO sheets. 1. Introduction The growing recent interest in graphene-based nanomaterials, largely because of their electronic structure and resulting interesting properties, has made it necessary to study them in more detail. Graphene Supermarket (https://graphene-supermarket.com/) claims that high surface area graphene structures can be used as reinforcements, conductive additives in composite or coating materials, supports for metallic catalysts, bio and chemical sensors, low-permeability materials, electrostatic dissipation (ESD) films, and fire retardants. The current two most straightforward and widely used techniques for determining the electronic structures of graphenes are angle-resolved photoemission spectroscopy (ARPES) [1–5] and near-edge X-ray absorption fine structure spectroscopy (NEXAFS) [6–9]. Another direct technique for investigating the electronic structures of solids is X-ray emission spectroscopy, which has been used to study carbon materials: graphite [10], carbon films [11, 12], carbon nanotubes [13], carbon fullerenes [14], and graphene nanoflakes with several graphene layers at the edges [15]. In numerous carbon-based structures, p-type electronic states are the main contribution to interatomic interactions [16]. To study the energy distributions of valence Cp electrons in carbon nanomaterials, it is necessary to investigate the C bands. Ultrasoft X-ray emission spectroscopy (USXES) yields comprehensive information about the energy distributions of occupied valence states lower
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